Every article tagged DevOps, in one place.
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Docker packages an application with everything it needs (runtime, libraries, config) into an image . Running an image creates a container : an isolated process that behaves the same on your laptop, a CI runner and a production server. Images vs containers An i...
Kubernetes runs containers across a cluster of machines and keeps them in the state you describe. You don't say "start three containers"; you declare "there should always be three", and Kubernetes makes it so, even when machines fail. Pod The smallest unit: on...
Monitoring tells you that something is wrong. Observability helps you understand why , including for problems you didn't predict. It's built from three kinds of telemetry. Metrics: numbers over time http_requests_total{route="/checkout", status="500"} 1243 htt...
A Dockerfile that "works" and one that's good for production differ in image size, build speed, security and how the app shuts down. Here's a solid template. # syntax=docker/dockerfile:1 # ---------- dependencies (all, for building) ---------- FROM node:22-alp...
Smaller images pull faster, start faster, cost less to store and contain fewer packages with vulnerabilities. Going from 1.2 GB to under 200 MB is common. 1. Choose a smaller base image node:22 (Debian full) - large, has build tools. node:22-slim - Debian with...
Containers isolate processes, but a careless image or run command can undo most of that protection. These practices close the common gaps. 1. Don't run as root RUN addgroup -S app && adduser -S app -G app USER app If an attacker exploits your app, they get the...
Most schema changes are instant. A few take heavy locks or rewrite entire tables, which can freeze a busy app. Knowing which is which is the key to safe migrations. Always set a lock timeout SET lock_timeout = '5s'; ALTER TABLE orders ADD COLUMN notes TEXT; Ev...
Helm is a package manager for Kubernetes. A chart is a bundle of templated manifests; a release is an installed copy of a chart with your settings ( values ). Installing software helm repo add bitnami https://charts.bitnami.com/bitnami helm search repo redis h...
On a table with hundreds of millions of rows, the wrong ALTER TABLE can lock writes for hours. MySQL offers several ways to avoid that. 1. Ask for INSTANT ALTER TABLE orders ADD COLUMN gift_message VARCHAR(255) NULL, ALGORITHM=INSTANT; Instant changes only tou...
Containers and process managers stop your app by sending SIGTERM . If you exit immediately, requests in progress fail and database transactions are cut off. A graceful shutdown finishes the current work first. The steps Stop accepting new connections. Let in-f...
A backup you've never restored is a hope, not a backup. Here's how to take consistent MySQL backups and prove they work. Logical backups with mysqldump mysqldump --single-transaction --routines --triggers --events \ --set-gtid-purged=OFF -h db -u backup -p sho...
